Apache Tomcat information disclosure vulnerability

 CVE-2010-1157: Apache Tomcat information disclosure vulnerability

Severity: Low

Vendor: The Apache Software Foundation

Versions Affected:
- - Tomcat 6.0.0 to 6.0.26
- - Tomcat 5.5.0 to 5.5.29
Note: The unsupported Tomcat 3.x, 4.x and 5.0.x versions may also be
affected.

Description:
The "WWW-Authenticate" header for BASIC and DIGEST authentication
includes a realm name. If a <realm-name> element is specified for the
application in web.xml it will be used. However, a <realm-name> is not
specified then Tomcat will generate one using the code snippet:
request.getServerName() + ":" + request.getServerPort()
In some circumstances this can expose the local hostname or IP address
of the machine running Tomcat.

Example:
GET /application/j_security_check HTTP/1.0

HTTP/1.1 401 Unauthorized
Server: Apache-Coyote/1.1
WWW-Authenticate: Basic realm="tomcat01:8080"
Content-Type: text/html;charset=utf-8
Content-Length: 954
Date: Thu, 31 Dec 2009 12:18:11 GMT
Connection: close

Mitigation:
Administrators of web applications that use BASIC or DIGEST
authentication are recommended to set an appropriate realm name in the
web application's web.xml file.
Alternatively, the following patches may be used to change the default
realm to "Authentication required" (without the quotes):
- - Tomcat 6.0.x: http://svn.apache.org/viewvc?view=rev&rev=936540
- - Tomcat 5.5.x: http://svn.apache.org/viewvc?view=rev&rev=936541
These patches will be included in the next releases of Tomcat 5.5.x and
Tomcat 6.0.x. No release date has been set for the next Tomcat 5.5.x and
Tomcat 6.0.x releases.

Credit:
This issue was discovered by Deniz Cevik.

References:
http://tomcat.apache.org/security.html
http://tomcat.apache.org/security-6.html
http://tomcat.apache.org/security-5.html